1. Field of the Invention
The present invention relates to the field of electric machines. It refers to an electric machine, in particular a generator or motor, said electric machine being accommodated in a machine housing and comprising a stator winding which passes through a stator core and which merges on the end face into an overhang which is mounted in a braced manner in order to absorb dynamic loads.
Such an electric machine is known, for example, from the publication EP-B1-0,432,720.
2. Discussion of Background
In the case of stator overhangs of large electric machines, such as, for example, turbogenerators, with a directly H.sub.2 -cooled stator winding, high dynamic stresses occur during operation, and these are to be absorbed and rendered harmless by suitably mounting the overhangs and keeping them braced in the mounting. The publication mentioned initially proposes bracing, in which the overhang rests on an inner ring and is pressed against the inner ring by suitable bracing means. In FIG. 4 of this publication, pairs of clamping wedges (16a, b) are proposed as bracing means, said clamping wedges pressing onto a clamping plate (transmitter 15a) and being supported on the inside of a supporting element (angle piece 13a) fastened to the stator core. The clamping wedges can be moved toward one another by means of a common clamping screw and thus press the clamping plate against the overhang.
One disadvantage of this type of bracing is that it is complicated to adjust and inflexible to handle. If the mechanical prestresses or the mounting geometry of the overhang change as a result of the loads occurring while the machine is in operation, these changes can be compensated only by shutting down the machine, opening the machine housing and suitably tightening the screw connections (of the clamping wedges) in the region of the overhang mounting. Problems presented by such maintenance are, on the one hand, the considerable downtimes of the machine which must be taken into account in addition to the actual maintenance outlay. On the other hand, however, readjusting the bracing itself also presents problems, since the effect of the readjustment can be checked with absolute certainty only while the machine is running, the ultimate result of this being that the machine is shut down and started up several times.